Control system



Jan. 5, 1937. I N, H, WlLLBY ET AL 2,066,920

CONTROL SYSTEM Filed Aug. 51, 1955 \NVENTORS W lT N ES SES:

hf Wi/ZZay, Fran/ *3 Powers ?atented Jon. 5, 1937 enrsu r dei ies.

@iDNTBUL SYSTEDI Norman H. Willby, Irwin, Frank B. Powers and John R Shemberger, Willrinsburg, Paw assigw ore to Westinghouse Electric & Manuiacturing Company, East Pittshurgh, Pa, a, corporation of Pennsylvania Application Augustin, 1935, Serial No. ZillJl-M 11 Claims.

@ur invention relates, generally, to control sy tems, and, more particularly, to systems for automatically controlling the acceleration and the deceleration 0i electrically propelled vehicles.

In view of the lightweight construction of some of the modern street cars, there is a great difference between the total weight when loaded and the car weight when empty. Therefore, the rate of both acceleration and braking decreases rapidly as the passenger load increases, which is particularly undesirable since the highest rates of acceleration and braking are needed when the load is heaviest.

an object of our invention is to maintain predetermined rates of acceleration and retardation of m electric vehicle irrespective of the load carried by the vehicle.

Another oloject oi our invention is to provide for selective acceleration and retardation of an electrically propelled vehicle.

A more general object of our invention is to provide an automatic control system which shall be simple and efiicient in operation and which may be economically manufactured and. installed.

Other objects of ourinvention will be fully explained hereinafter or will be apparent to those skilled in the art.

In accordance with one embodiment of our invention, coth the acceleration and the retardation of an electric vehicle are governed by a pendulum device which functions to cause preselected rates of acceleration and deceleration to he maintained irrespective of the load on the vehicle. Pro vision is made for preselecting the rates of acceleration and deceleration by controllers which are operated by the vehicle operator and are connected to the pendulum device icy variable loading springs. The pendulum device governs the operation of the control equipment, including a magnetic track brake, thereby controlling the acceleration and the deceleration of the vehicle.

For a fuller understanding of the nature and ObjECtSgOZ our invention, reference may be had to the following detailed description, taken in conjunction with the accompanying drawing, in which the single figure is adiagrammatic view of acontrol system embodying our invention.

Referring to the drawing, the system shown comprises motors l0 windings l2 and i3 and series field windings l4 and i5, respectively; a line switch it, a plurality of accelerating switches. l1, l8, l9 and 20 for shunting a resistor 2| from the motor circuit to accelerate the motors l0 and H; an additional switch 22 for completing the motor circuit during and ii having armature (\Cl. In 119) or drum Tl driven by an air engine 28 for con- Y trolling the operation oi the resistor shunting switches ll to ill, inclusive; an accelerating controller 3i and a braking controller 32 which both oi the drum. type, well known the art. As shown, the controllers 3i and 532 are elec trically interlocked, however, they may he also mechanically interlocked to prevent improper op eration of the controllers and the equipment controlled. thereby.

AS fully described in Patent No. 1394,92 1, issued January 24, 1933, to B. 0. Austin et al., and assigned to the Westinghouse Electric ll; lvianufacturing Company, the foregoing apparatus may be utilized to control both the acceleration and the retardation of an electrically propelled vehicle and to provide for variable rates of acceleration and deceleration, which may ice selected by the operator to meet varying traffic conditions.

However, the system described in the foregoing in view of the lightweight construction oi modern street cars.

' In order that constant preselected rates of acceleration and deceleration may be maintained irrespective of the load on the vehicle, a pendulum device 33 is so mounted on the vehicle that it is responsive to the rates of acceleration and deceleration of the vehicle. The pendulum device 33 is disposed to control the operation of an air engine 3A, which drives a drum switch 35 having contact segments 36 and 31. The contact segment 35 is utilized for shunting a resistor 38 from the circuit for the loading coil 26 of the limit relay 25, thereby varying the current in the loading coil 26 and governing the operation of the' limit relay. The contact segment 31 is disposed to shunt a resistor 39, step-by-step, from the circuit for the electromagnet of a magnetic track brake M, which is utilized to assist in retarding the vehicle in a manner which will be more fully described hereinafter.

With a view to permitting the operator of the vehicle to select the rates of acceleration and deceleration which he desires to maintain, s rings 42 and 43 are so connected between the ndulum device 33 and the controllers 3! and 32, respectively, that the tension of the springs may be increased by operating the controllers, thereby governing the operation of the pendulum device 33 to increase or decrease the rates of acceleration and deceleration, which will be automatically maintained by the control system herein described.

In order that the functioning of the foregoing apparatus may be more clearly understood, the operation of the system will now be described in more detail. Assuming that it is desired to operate the vehicle in the direction indicated by the arrow shown above the track brake 4|, the controller 3| may be actuated to a position (1", thereby closing the line switch 18 and the switch 22 to connect the motors I8 and I I to a power conductor 5|. The energizing circuit for the actuating coil of the switch l8 may be traced from the power conductor 5|, through a trolley 52, conductors 53 and 54, contact fingers 55 and 58 bridged by a contact seg ment 51 of the controller 3|, conductors 58 and 58, the actuating coil of the switch l6, conductor 8|, an interlock 82 on the braking switch 23, which must be in the open position, conductors 83 and 84, a contact segment 85 on the sequence drum 21 which is in the 011" position, and conductor 88 to the grounded conductor 81. The energizing circuit for the switch 22 extends from the previously energized conductor 58 through the actuating coil of the switch 22 and conductors 88 and 89 to the grounded conductor 81.

The motors l8 and II are now connected in parallel-circuit relation and are connected to the power conductor 5| in series with the resistor 2|. The circuit for the motor |8 may be traced from the power conductor 5|, through the trolley 52, conductor 53, contact member 1| of the line switch IS, the resistor 2|, conductor 12, contact members 13 of the switch 22, the series field winding l4, and the armature winding |2 of the' motor I8 to the grounded conductor 61. The circuit for the motor extends from the switch 22 through conductor 14, the armature winding l3 and series fleld winding l5 of the motor conductor 15, the actuating coil 25 of the limit relay 24 and conductor 18 to the grounded conductor 81.

Since all of the resistor 2| is connected in series with the motors |8and II, the motors will operate at a low rate of speed. If it is desired to accelerate the motors, the controller 3| may be actuated to position b which will cause the air engine 28 to operate the sequence switch 21 through positions I to 4, inclusive, to close the resistor shunting switches H to 28 in sequential relation, thereby accelerating the motors l8 and II in a manner well known in the art.

The air engine 28 is so constructed that it will advance the sequence switch or drum 21 when the actuating coils 11 and 18 of magnet valves 18 and 8|, respectively, are both energized. The energizing circuit for the actuating coil 11 may be traced from a contact finger 82, which engages the contact segment 51 of the controller 3|, through conductors 83 and 84, the actuating coil 11, conductors 85 and 63, an interlock 88 on the line switch l8, which also functions to establish a holding circuit for the switch l8, and conductor 88 to the grounded conductorf 61. The circuit for the actuating coil of the magnet valve 8| may be traced from a contact finger 81, which engages the contact segment 51, through conductors 88 and 89, contact member 9| on the limit relay 24, conductor 82, the actuating coil 18 and thence to the grounded conductors 81 through the circuit just previously traced for the coil 11.

As the sequence drum 21 is advanced through positions I to 4, the actuating coil 01' the switches H to 28, inclusive, are energized in sequential relation. The energizing circuit for the switch |1 may be traced from the previously energized conductor 84 through conductor 83, contact fingers 94 and 95 bridged by contact segment 96 of the drum switch 21, conductor 91. the actuating coil of the switch i1 and conductors 98, 98 and 69 to the grounded conductor 81. It will be seen that conductors |8|, |82 and I83 are energized to operate the switches l8, l3 and 28, respectively, in a similar manner as the sequence switch 21 advances step-by-step.

However, as is fully explained in the foregoing Patent No. 1,894,971, the advancement of the sequence switch 21 by the air engine. is automatically controlled by the limit relay 24, which is responsive to the motor current, thereby preventing the sequence switch 21 from-being advanced so rapidly that the motor current is excessive. It will be understood that the motor current is increased as each step of the resistor 2| is shunted from the motor circuit. The increase in the motor current causes the relay 24 to be operated to its uppermost position, thereby deenergizing the actuating coil of the magnet valve 8| which stops the advancement of the sequence switch 21. As the motors accelerate in speed, their counter-electromotive force is increased, thereby reducing the motor current which permits the limit relay 24 to drop to its lowermost position to energize the actuating coil of the magnet valve 8| and cause the sequence drum to advance to another position. It will be observed that the sequence drum 21 is provided with carryover contact segments I84 to prevent the stopping of the sequence drum 21 between positions by the deenergization of the magnet coil 18 as a result of the operation of the limit relay 24.

As described in the foregoing Patent No. 1,894,971, the operation of the limit relay 24 and, therefore, the rate of acceleration of the motors 8 and II may be governed by varying the current in the circuit for the loading coil 28 which is disposed to oppose the actuating coil 25 of the limit relay. By increasing the current in the loading coil 26, the amount of current required to operate the relay 24 is increased, which permits the motor current to be increased, thereby increasing the rate oi acceleration oi the motors.

As stated hereinbei'ore, the pendulum device 33' is utilized to control the operation oi. an airoperated drum switch 35 which shunts the resistor 38, step-by-step, from the circuit of the loading coil 26, thereby governing the operation of the limit relay 24. The air engine 34, which drives the drum switch 35, is so constructed that the drum switch 35 is held in the 011" position when the actuating coils I85 and I88 oi the magnet valves I81 and I88, respectively, are both energized.

As shown, the magnet coils I85 and I88 were energized so long as the controller 3| was in the oiP' position. The energizing circuit for the magnet coil 85 may be traced from the previously energized conductor 54 through conductors III and 2, the magnet coil I85, conductor H3, contact fingers H4 and lllbridged by contact segment IIS on the braking controller 3E2, conductor ll'l', contact fingers H8 and i l9 bridged by a contact segment I2I on the controller 3i and conductor I22 to the grounded conductor iii. The energizing circuit for the magnet coil ltd extends jirom the previously energized conductor H2 through the coil Hi6, conductor 6233, contact fingers I24 and I25 bridged by contact segment E26, conductor i2'l, contact fingers ltd and lit bridged by the con tact segment l2l and conductor F22 to the grounded conductor t'i.

However, when the accelerating controller 3i is actuated to position b, as has been pre- 15 viously assumed, the magnet coils ltd-and tilt advanced, first to energize the loading coil y connecting it across the power source in with the resistor and. then to shunt from'the loading coil circuit, y increasmg the current in the loading coil. ne circuit for the loading coil may be from the previously energized conductor ill tin'ough conductor I29, the resistor 38, contact fingers ml and I32 bridgcdby the contact segment 36, conductor $3, the loading coil 26 and conductor to to the grounded conductor 61?.

Assuming that the vehicle is moving in the direction indicated by the arrow above the track rake ll it will be understood that the acceleration of the vehicle will cause the pendulum device 33 to swing in a direction to engage a resiliently mounted contact member I34 which establishes an energizing circuit for the magnet coil tile, thereby stopping the travel of the drum switch 355 which regulates the current in the loading coil 2t and governs the operation of the limit relay 2d which, in turn, governs the rateof acceleration of the motors ill and II. The energizing circuit for the magnet coil I06 established by the pendulum device 33 may be traced ,from the previously energized conductor II2 through the magnet coil I06, conductor I23, contact fingers 524 and I35, bridged by the contact segment 926 on the controller 32, conductor lSB, contact members I34 on the pendulum device 33, and conductors I3I and I22 to the grounded conductor 61.

If the vehicle is accelerating at such a rate that the pendulum device 33 swings to a position in which its contact members I38 are closed, an energizing circuit is established for the magnet coil Illd which causes the air engine 34 to return the drum switch toward the oil' position, thereby increasing the resistance in the circuit for the loading coil of the relay 26 and reducing the rate of acceleration of the motors by. decreasing the mo or current rmuired to op crate the limit relay 24, which, in turn, governs the operation of the sequence switch 21 as hereinbefore explained.

The energizing circuit for the magnet coil I05 may be traced 10m the previously energized conductor, II2 through. the coil I05, conductor H3, contact, fingers lid and MI bridged by the contact segment H6, conductor M2. contact members I38 on the pendulum device 33, and conductors I31 and I22 to the grounded conductor 61. In this manner, the pendulum dewice 33 functions to govern the rate of acceleration of. the vehicle and to maintain the preselected rate of acceleration irrespective of the load carried by the vehicle.

It will be seen that the'tension of the spring 42 is controlled by, means of the accelerating both deenergized and the drum switch controller 3i, which is manually operated by the operator of the vehicle. Therefore, the movement of the pendulum device 33 may be governed by the operator, who may thereby select the rate at which he desires the vehicle to accelerate. Thus, by actuating the controller 3i to positions 02, or e, a higher rate of acceleration is obtained than when the controller is on positions b or "c, since the tension of the spring 12 is increased which increases the loading on the pendulum device It will he understood that the pendulum device 33 functions to maintain the preselected rate of acceleration irrespective of the load carried by the vehicle, since the movement entirely dependent upon the rate of acceleration of the vehicle. Therefore, the accelerating controller is actuated to position for the maximum rate of accelerat' n the pendulum device ill not function to the progression of the drum switch until the preselected rate for acceleration is attained. Therefore, the drum switch will advance to permit the maximum current in the loading coil which so governs the operation of the limit relay 2d that the sequence switch 21 will advance at its maximum rate which in turn will cause maximum acceleration of the motors Hi and ii. However, should the vehicle accelerate at a rate above that selected by the operator, the drum switch 35 is returned to a position which will provide the desired rate of ac coloration, as hereinbeiore explained.

The control system herein described will also automatically control the rate of deceleration or retardation of the vehicle in a manner similar to that of controlling the rate of acceleration. Provision is made for retarding the vehicle both by a dynamic brake and also by means of a magnetic track brake M which is coordinated iivlith the dynamic braking of the motors it and Dynamic braking may be established by first actuating the controller 3i to the off position and then actuating the braking controller 32 to either one of the braking positions, a, b, c, d, or e, the rate of retardation being controlled by the position of the controller 32.

When the braking controller 32 is actuated to position a, the switch 23 is closed to establish dynamic braking connections for the motors Ill and II. The energizing circuit of'the loading coil of the switch 23 may be traced from the positive conductor 54 through contact members 55 and I 43 bridged by the contact segment El on the controller 3i, conductor IM, contact members I45 and M6 bridged by a contact segment M1 on the controller 32, conductor Mil, the actuating coil 23, conductor I49, an interlock ltll on the switch iii, conductors 63 and 65, contactsegment 65 on the sequence switch 2i, which was returned to the off position when the controller 3I was actuated to the ofi position, and conductor 66 to the grounded conductor 61. A holding circuit is established for the actuating coil of the switch 23 through its contact members I52 when the switch is closed.

The closing of the switch 23 establishes dynamic braking connections for the motors I0 and II in a manner well known in the art, the re-f sistor 2i being so connected in the motor circuit that the motor current may be controlled by shunting the resistor by means of the switches H to 29, inclusive, in the same manner as during the acceleration of the motors. The motors I0 and II are so connected that the field winding I4 of the motor I is in series with the armature winding I3 of the motor II, and the field winding I is in series with the armature winding I2 of the motor I0, thereby permitting the current to flow through the field windings in the same direction as during acceleration and through the armature windings in the reverse direction, which causes the motors to act as generators to retard the movement of the vehicle. The circuit through the field winding I4 may be traced from one side of the armature I3, conductor 14, field winding I4, contact members I55 on the switch 23, conductor I56. the resistor 2|, conductor I51, contact members I59 on switch 23, and conductor I59 to the other side of the armature I3. The circuit through the field winding I5 may be traced from one side of the armature winding I2 of the motor I0 through the contact members I55 on the switch 23, conductor I56, resistor 2i,

conductor I51, contact members I58, conductor I59, the field winding I5, conductor 15, the actuating coil 25 of the relay 24 and conductors I6 and 61 to the other side of the armature winding I2.

It will be observed that the magnet coils 1I and 18 of the air engine 28 are energized through circuits established by the contact fingers I6I and I62 which engage the contact segment I41 on the controller 32, thereby causing the scquence switch 21 to be advanced under the con trol of the limit relay 24, as hereinbefore explained, to shunt the resistor 2I from the motor circuit by means of the switches I1 to 20, inelusive, which are actuated in sequential relation. The pendulum device 33 functions to maintain a predetermined rate of deceleration by controlling the operation of the drum switch 35, which in turn governs the operation of the limit relay 24. Themagnet coils I05 and I06 were both deenergized when the controller 32 was actuated from its off position, thereby causing the drum switch 35 to be advanced to shunt the resistor 38 from the circuit for the loading coil 26, as has been described hereinbefore.

If the rate of deceleration is such that the pendulum device 33 swings to a position in which its contact members I63 are closed, the magnet coil I06 is energized to stop the progression of the drum switch 35. The circuit through the magnet coil I06 may be traced from the previously energized conductor II2 through the coil I06, conductor I23, contact fingers I24 and I64, bridged by contact segment I26, conductor I65, contact members I63 on the pendulum device 33 and conductors I31 and I22 to the grounded conductor 61.

I! the rate of deceleration is still further increased, the pendulum device 33 will swing to a position in which its contact members I66 are closed, thereby energizing the magnet coil I05 through a circuit which extends from the conductor II2 through the coil I05, conductor H3, contact fingers H4 and I61, conductor I63, contact members I66 on the pendulum device 33 and conductors I31 and I22 to the grounded conductor 61, which causes the drum switch 35 to be returned toward its off position. In this manner, the pendulum device 33 functions to maintain the preselected rate of deceleration by controlling the motor current as herein described. In addition to controlling the motor current during dynamic braking of the motors, the pendulum device 33 also controls the energization and, therefore, the braking effect of the magnetic track brake 4|, thereby causing the track brake to cooperate with the motors I0 and II in controlling the retardation of the vehicle. The electro-magnet I69 01' the magnetic track brake 4| is energized through a circuit which may be traced from contact finger I1I which engages the segment I41 on the controller 32 through conductor I12, resistor 39, contact fingers I13 and I14 bridged by the contact segment 31, conductor I15, the electromagnet I69 and conductors I16 and I22 to the ground conductor 61.

It will be seen that the resistor 39 is shunted from the circuit for the electromagnet I69 as the drum switch 35 is advanced by the air engine 34. Since the operation of the air engine 34 is governed by the pendulum device 33, as herein explained, the effect of the track brake 4| is controlled by the pendulum device 33, and the track brake 4|, therefore, cooperates with the motors I0 and II to control the retardation of the vehicle. In a similar manner the pendulum device 33 and the drum switch 35 may be utilized to coordinate air brakes with the dy- ;namic brake to provide the desired braking effect.

It will be understood that the rate of deceleration may be increased by actuating the controller 32 toward position e, which permits the operator to select the desired rate of deceleration in the same manner as the rate of acceleration of the vehicle. The tension of the spring 43 is increased as the braking controller 32 is actuated toward position "e, thereby controlling the movement of the pendulum device 33, which functions to maintain the preselected rate of deceleration, as herein described.

From the foregoing description, it will be apparent that we have provided a control system which will automatically govern both the acceleration and the deceleration or retardation of an electrically propelled vehicle and which will function to maintain the preselected rates of acceleration and deceleration irrespective of the load carried by the vehicle. The system herein described permits the operator of the vehicle to select the rates of acceleration and deceleration which are most suitable for the traffic conditions encountered, and provides for maintaining the selected rate.

Since numerous changes may be made in the above-described construction and different embodiments of the invention may be made without departing from the spirit and scope thereof, it is contended that all matter contained in the above description or shown in the accompanying drawing shall be determined as illustrative and not in a limiting sense.

We claim as our invention:

i. In a motor control system, in combination,

an electric motor for propelling a vehicle, manually-operable means for controlling the motor connections, means for controlling the acceleration of the motor, means actuated in accordance with the amount of motor current for controlling the operatlon of the acceleration-controlling means. means responsive to the rate of acceleration of the vehicle for governing the operation of the currentresponsive means, and means adjusted by said manually-operable means for governing the operation of the last-named means to vary the rate of acceleration of the vehicle.

2. In a motor control system, in combination, an electric motor for propelling a vehicle, a manually-operable controller, switching means for controlling the acceleration of the motor, means for controlling the operation oi the eration of the vehicle for governing the operation of the current-responsive means, and means associated with said controller for governing the operation of the last-named means.

3. In a motor control system, in combination, an electric motor for propelling a vehicle, a man'- ually-operable controller, switching means for controlling the acceleration-of the motor, means responsive to the motor current for controlling the operation of the switching means, means responsive to the rate of acceleration of the vehicle for governing the operation of the cur--' rent-responsive means, and means actuated by said controller for governing the operation of the last-named means.

4. In a motor control system, in combination, an electric motor for propelling a vehicle, a manually-operable controller, switching means for controlling the acceleration of the motor, relay means responsive to the motor current for controlling the operation of the switching means, means for varying the current required to operate said relay means, means responsive to the rateof acceleration of the vehicle for controlling the operation of said current-varying means, and means associated with said controller for governing the operation of the last-named means.

5. In a motor control system, in combination, an electric motorfor' propelling a vehicle, a manually-operable controller, switching means :for controlling the acceleration of the motor;

relay means responsive to the motor. current for controlling the operation of the switching means, means for varying the current required to operate said relay means, means responsive to the rate of acceleration of the vehicle for controlling the operation of said current-varying means, andspring means biased by said controller for governing the. operation of the lasthamed means.

6. In a motor control system, in combination, an electric motor for propelling a vehicle, a manually-operable controller, switching means for controlling the acceleration of the motor, re,- lay means for controlling the operation of the switching means in accordance with the motor current, said relay means having an actuating coil and a loading coil disposed to oppose the actuating coil, means for varying the current in the loading coil, means responsive to the rate of acceleration of the vehicle for controlling the,

operation of said current-varying means, and means actuated by said controller for governing the operation of the last-named means.

7. In a motor control system, in combination, a plurality of electric motors for propelling a vehicle, a manually-operable controller, means for establishing dynamic braking connections for the motors to decelerate the vehicle, switching means .for controlling the deceleration of the motors,-

means responsive to the motor current for controlling the operation of the switching means, means responsive to the rate of deceleration of the vehicle for governing the operation of the current-responsive means, and spring means biased by said controller for governing the operation of the last-named means.

8. In a motor control system, in combination,

a plurality of electric motors for propelling a vehicle, a manually-operable controller, means -for establishing dynamic braking connections a plurality of electric motors for propelling a vehicle, means for connecting the motors to a power source to accelerate the vehicle, means for establishing electrical braking connections for the motors to decelerate the vehicle, additional means for braking the vehicle, switching means for controlling the acceleration and the deceleration of the motors, means for controlling the operation of the switching means in accordance with motor current, and means responsive to the rates of acceleration and deceleration of the vehicle for governing the operation of said control means and said additional braking means.

10. In a motor control system, in combination,

a plurality of electric motors for propelling avehicle, means for connecting the motors to a.- power source to accelerate the vehicle, means for establishing electrical braking connections for the motors to decelerate the vehicle, additional means for braking the vehicle, switching means for controlling the acceleration and the deceleration of the motors, means responsive to the motor current for controlling the operation of the switching means, means responsive to the rates of acceleration and deceleration of the vehicle for governing the operation of the current-responsive means and said additional braking means, and means for governing the operation of the last-named means to vary the rates of acceleration and deceleration of the vehicle.

11. In a motor control system, in combination, a 'plurality of electric motors for propelling a vehicle,'means for connecting the motors to a power source to accelerate the vehicle, means for establishing electrical braking connections for the motors to decelerate the vehicle, switching means for controlling the acceleration and the deceleration of the motors, means responsive to the motor current for controlling the operation of the switching means, means responsive to the rates of acceleration and deceleration of the vehicle for governing the operation of the currentresponsive means, and means cooperating with the last-named means to control the operation of additional braking means for the vehicle.

NORMAN I-I. WILLBY. FRANK B. POWERS. JOHN P. SHAMBERGER. 

